1. Field of the Disclosure
The disclosure relates generally to the field of wearable computing systems and subsystems, such as methods and systems involving an item of jewelry such as a watch or a bracelet worn on a wrist of a user that may contain a coil for generating a magnetic field to inductively power a second piece of jewelry such as a ring that may contain an LC (“tank”) circuit that may oscillate at a resonant frequency.
2. General Background
An inductor (L) and a capacitor (C) may be used together in a circuit typically referred to as a LC circuit, an LC tank circuit, an LC tuned circuit, or a resonant circuit to tune to specific frequencies. As is commonly known, an LC tank circuit may oscillate at a resonant frequency, and be used to isolate a signal at a particular frequency from a more complex signal. For example, a radio receiver typically has an antenna connected to a variable LC tank circuit, to tune to a desired LC resonant frequency among the signals coming in from the antenna, such as a specific radio station. If an LC tank circuit is connected to a power source, it may oscillate at a resonant frequency. The oscillation may be due to the effect of the magnetic field of the inductor increasing and then collapsing as the capacitor charges and then discharges.
An inductive power transfer may be used to power a device without the need for any direct wired connection between the power source and the device. Inductive power transfer may use a primary coil and a secondary coil. The primary coil may be contained within the device under power. The primary coil may have a current passing through it, which generates a proportional magnetic field around the primary coil. If a secondary coil is placed within the primary coil's magnetic field, the electromagnetic waves generated by the current passing through the primary coil cause a current to be induced through the secondary coil. This process is known as magnetic induction. The current in the secondary coil may then be utilized to power another device that is coupled to the secondary coil. The secondary coil may be contained, for example, within a receiving system that may be powered through this process of magnetic induction. When the receiving device is placed near the primary coil, power may be inductively transferred from the primary coil to the secondary coil, with no direct electrical (wired) connection between the coils. Common examples of commercially available devices that use this type of inductive charging include cordless toothbrushes.
It is desirable to apply the above principles to the field of wearable computers, such as by using items of jewelry as controllers for computer applications, including but not limited to gaming software.